I am writing from Harbin, a city in northeast China north of North Korea and just south of Russian Siberia. I am at the newly-renovated Unit 731 Museum, the site of a Japanese bacteriological warfare unit in 1938 in the village of Pingfan that was 20 miles south of Harbin—today a suburb of the growing city of Harbin. And I will caution readers that this history of wartime atrocity far exceeds the depravity of German doctors brought to trial at Nuremberg.

Japan had controlled this area (Manchuria) since 1905. Planning for war with China, Japan sent Ishii Shiro to establish a biowarfare facility here at Pingfan, hidden far from public scrutiny. Ishii’s mission was to develop germ warfare for use against enemy troops and civilians. Over 30 disease agents were studied for military use, including cholera, anthrax, typhoid, salmonella, bubonic plague and typhus.

Unit 731 grew large vats of cholera bacteria, a water-borne disease that caused death by diarrhea and dehydration. In the first battlefield deployment of these germs, some Japanese troops also contracted the illnesses. And the impact on the enemy and wider civilian population was mild. To Ishii’s dismay, they discovered that the environment rapidly diluted and killed disease agents. He needed a way for his disease agents to be protected and find their human targets. He shifted his team’s research to insect-vectored diseases: flea-borne bubonic plague and louse-borne typhus. He would enlist insects into war.

And I am an entomologist. That is what brings me to this Unit 731 Museum today. Robert Oppenheimer remarked upon the successful test of the atomic bomb that now "...physicists have known sin." Here at Pingfan, with the corpses and ashes of the victims of biowarfare experimentation buried under the ground on which I stand, is where entomology became evil.

Ishii pioneered work into the cultivation of the most dreadful of diseases. Bubonic plague became a major focus. Ishii’s teams worked to culture the most virulent strains of plague using fleas on mice and ground squirrels. How to grow germs without infecting the scientists or army personnel that would distribute the disease meant inventing better hazmat suits. They had to seal off their sick animal colonies from outside animals. Systems to safely distribute fleas in enemy territory had to be developed.

But it was in testing the virulence of bacterial strains on human victims that Ishii set a new standard for cruelty. Because bodies of victims who died of bubonic plague rapidly decay, they conducted the "autopsy" while the victim was still living in order to detect the organ damage before death. Anaesthesia was not used. Young Japanese doctors found their first operations to be disturbing but soon got accustomed to the screaming as a victim was sliced open with a scalpel. Humans treated as "experimental animals" were casually referred to as "maruta"—Japanese for "logs." Films of these procedures were distributed in the military and over 100 science articles were published, often citing the use of "Manchurian monkeys" when there were no real monkeys in Manchuria.

Unit 731 Department Head Kawashima confessed that "...at least 3,000 people were used as subjects of live body experiments during the years from 1940 to 1945." These victims, originally just kidnapped from city streets, were eventually "special transfer" prisoners of war or captured enemy spies. As you walk this museum, you can witness the original records, descriptions and drawings by Japanese doctors who detailed their "living autopsies."

Plague fleas were mixed with sand and the mixture was placed in a porcelain bombshell. These bombs were dropped from planes and exploded about 300-500 feet above ground, with 80 percent of fleas surviving the explosion. To test the effectiveness, healthy prisoners were tied to crosses arranged in a large circular target area. Within a short time after a bomb was dropped, the infected fleas found the bound prisoners, most of whom died in 2 to 10 days of plague.

Because of the difficulty of determining biological warfare deaths that come months or years after the attack, exact numbers cannot be known. But aerial bombardment of Chengte, Ningo and over a dozen other Chinese cities resulted in huge numbers of casualties. Jeffrey Lockwood, author of "Six-legged Soldiers" concludes that the "accepted figure" of deaths due to Unit 731 Japanese biological warfare is "...a total of 580,000 Chinese...killed—slightly more than three-fourths by entomological weapons."

Ishii noticed that starvation took an even heavier toll. He began developing agricultural pests to spread in enemy territory to destroy crops. However, Japan was losing the war and time ran out at Hiroshima and Nagasaki. Realizing the likely consequences of the discovery of Unit 731 activities after Japan’s surrender on August 14, Ishii ordered Chinese laborers to destroy Unit 731—and then executed them.

You and I might assume that Ishii Shiro and the ranking officials of Unit 731 would soon stand trial for war crimes.